A footwear such as shoes, socks, and the like is knitted using a flat knitting machine. For example, in the socks, a sole cover section that covers a sole of a wearer; an instep cover section that covers an instep side portion of the wearer; and a body section that is connected to the instep cover section and covers a portion on the upper side from a vicinity of an ankle of the wearer are conventionally knitted integrally in a seamless manner. In the knitting of the socks, the knitting width of the socks is widened at the portion corresponding to a heel in order to make the socks lie along the shape of the foot, in particular, the shape of the heel of the wearer (see e.g., Patent Document 1).